Watch crystal and casing assembly



oct. 21, 1969 J. GLASS 3,473,319

WATCH CRYSTAL AND CASING ASSEMBLY Filed Nov. 13, 1967 Afa/20772@ Glass 11%@ @wwZZ/J//zejee United States Patent O FPice Int. Cl. G04b 39/00 U.S. Cl. 58-91 7 `Claims ABSTRACT OF THE DISCLOSURE The disclosed watch crystal provides an improved seal with a peripheral casing member while compensating for dimensional variations in manufacture of the watch beyond normal tolerances. Specifically, the interior wall portion of a peripheral casing member includes an 1nwardly extending peripheral flange, the top surface of the flange conventionally providing a seat for the transparent crystal and the bottom surface a stop abutment for the dial of the watch mechanism. The watch crystal is undercut about its periphery to define a stepped shoulder portion, preferably adapted to extend contiguous to the interior face of the peripheral flange and to terminate in a common plane with the bottom surface of the flange, thereby providing a seal of increased length between the casing member and the crystal, while also effectively 1ncreasing the inward extent of said flange to provide an abutment of adequate dimensions for the dial of the watch mechanism. Other features are disclosed.

INTRODUCTION The present invention relates generally to watches and, more specifically, to a new and improved watch crystal and casing assembly.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a new and improved transparent crystal for a wristwatch or the like as well as an improved crystal and watch assembly.

It is another object of the present invention to provide a seal of substantial length and non-linear outline between a crystal and a peripheral casing member of a watch thereby to reduce the probability of dust or other foreign matter entering the casing.

It is a further object of the present invention to provide a watch crystal that effectively compensates for dimensional variations beyond normal tolerances between the dial and locating flange of the peripheral casing member of the Watch to the end that the dial is firmly and positively positioned within the peripheral casing member.

It is yet a further object of the invention toprovide a watch crystal construction that enables convenient removal of the crystal from the casing by conventional tools and without the likelihood of scratching the face of the crystal.

Accordingly, the invention relates to a watch of the type including a peripheral casing member having an interior wall portion defining a central opening in the casing member and having an interior peripheral flange member of predetermined thickness extending inwardly from the interior wall portion. Specifically, the invention is directed to a transparent crystal member adapted to seat against the top surface of the flange member with the periphery of the crystal contiguous, and preferably in compressed engagement, with the interior wall portion of the peripheral casing member. The crystal member also includes an integral stepped shoulder portion adapted to extend below the top surface of the flange for at least 3,473,319 Patented Oct. 21, 1969 a portion of the thickness thereof with the shoulder portion being substantially contiguous to the interiorally facing surface of the flange member.

`BRIEF DESCRIPTION OF THE DRAWINGS The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention together with further objects and advantages thereof may best be understood, however, with reference to the following description taken in connection with the acocmpanying drawings in the several figures of which like reference numerals identify like elements and in which:

FIGURE 1 is a perspective view, partly in section, of a wristwatch embodying the present invention;

FIGURE 2 is a perspective view of the several cornponents of the watch positioned in the order of their assembly;

FIGURE 3 is a cross-sectional view taken along lines 3 3 of FIGURE l; and

FIGURE 4 is an exploded fragmentary view taken along section lines 4-4 of FIGURE l.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGURE l, there is shown a wristwatch 10 including a peripheral or outer casing member 12 having the usual integral support arms on opposite sides of the case for accommodating a conventional wristband or strap 14. A protective enclosure is provided for a contained watch mechanism 18, partly visible in FIGURE l, `by a conventional transverse bottom casing member 20, likewise only partly visible in the figure, and a transparent watch crystal 22.

In accordance with the present invention, the transparent crystal 22 is adapted to cooperate with the peripheral casing member 12 so that certain dimensional discrepancies beyond normal tolerances inherently encountered in the manufacturing process are effectively compensated, and also a more effective seal obtained between the casing and the crystal. To this end and as will presently be explained in greater detail, the crystal 22 is peripherally undercut to define a stepped shoulder portion 22a adapted closely to follow the contour of a conventional peripheral flange member 24 of the casing 12. As will likewise be considered in detail somewhat later herein, the crystal 22 is provided with an exterior or outer peripheral shoulder portion 25 to facilitate removal of the crystal from the casing 12 without scratching or otherwise injuring the smooth crystal surface.

As shown more clearly in FIGURE 2, the annular flange 24 extends inwardly from an annular interior wall portion 26 of the casing member 12; the flange 24 effectively divides the casing member into upper and lower casing sections for reasons that will presently become apparent. The lower casing section is adapted to receive the watch mechanism 18, only diagrammatically illustrated in the figure as it forms no part of the present invention. The watch mechanism 18 is provided with a circular dial 28 and a bottom casing member 30` adapted to -be received in locking engagement with the lower surface of the peripheral casing member 12.

Under the influence of the transverse casing member 30 and the intermediate watch mechanism 18, the dial 28 is adapted firmly to abut the bottom surface of the peripheral flange 24 and retain the various components firmly assembled. As pointed out previously, however, the relative dimensions of the flange 24 and the dial 28 are often such that the dial is not adequately retained in position with the result that the dial may partially or totally move above the flange thereby necessitating disassembly and repair of the watch. The machining of the iiange 24 is expensive and time consuming since the casing 12 is typically formed of a relatively hard metal. Furthermore, it is not acceptable to permit the flange t extend radially inward by a sufiicient distance to accommodate any possible tolerance error, since the flange 24 Would then be overly conspicuous as viewed through the transparent crystal and detract from the essential asthetic aspects of the watch design.

It is also a long standing problem in the art that watch crystals, due to an initially poor lit between the crystal and the casing member, or later shrinkage of the crystal, often effect an unsatisfactory seal with the casing member to permit condensation or dust to enter the Watch enclosure and detract from the appearance of the dial and/or impair operation of the watch mechanism.

In accordance with the present invention, both of the foregoing problems are effectively obviated by the disclosed watch crystal construction 22. Preferably, the crystal 22 is prepared from a high quality co-polymer sheet material of a type not subject to discoloration. The sheet material, preferably of a .070 inch thickness, is cut into a series of square blanks of appropriate size and a protective masking is removed therefrom. The individual blanks are fed in succession to suitable forming dies which shape the blanks to the desired concaveconvexity of the finished watch crystal.

Subsequent to the forming operation, the partially completed crystals are annealed by heating them to a suitable treating temperature and then permitting them to cool over a relatively long period, such as 12 to 24 hours. The tempered and cured crystals are then turned on a lathe to remove the excess portions of the blanks and provide a peripheral undercut defining the annular shoulder portion 22a of the crystal 22. The undercut is formed to complement the ange 24 so that upon insertion of the crystal into the upper section of the casing member, the crystal will be seated contiguous to the top surface of the flange 24 as well as to the interior vertical face portion of the fiange, as shown in FIGURE 3.

The peripheral or outer dimensions of the crystal 22 are preferably slightly larger than the internal dimensions of the casing member 12 and its integral flange 24. The crystal 22 is pressed into the casing 12 where, because of its larger dimensions, the crystal is maintained under compression thereby. The annealed co-polymer crystal member 22 is of a temper so as not to be permanently deformed, caused to shrink, or otherwise impaired, by virtue of its assembly under compression. Furthermore, the crystal 22 and its integral shoulder portion 22a are of sufcient resilience closely to conform to the upper section of the interior wall portion 26 and the annular flange 24 of the casing member 12. Hence, a satisfactory seal is maintained between the crystal and the casing by the mere seating of the crystal therein, although it is understood that a suitable transparent sealing cornpound or the like may be inserted between these members if desired.

Referring now to FIGURE 4, the contiguous seating of the crystal 22 in the casing member 12 can be appreciated in greater detail. Specifically, it will be observed that the shoulder portion 22a extends below the top surface of the flange 24 and preferably terminates in a plane which is co-extensive with the bottom surface of the ange. This structural relationship provides a seal of exceptional length having two right angle bends in a Z- like configuration thereby effectively reducing the probability that condensation or other foreign matter will enter the watch enclosure. Furthermore, by making the bottom of the shoulder 22a co-planar with the bottom of the flange 24, the inward extent of the ange is effectively increased and the previously discussed manufacturing dimensional variations effectively compensated, while the ltransparent shoulder 22a of the crystal does not detract from the asthetic appearances of the watch dial or the like. The abutment of the dial 28 against the flange and shoulder portion 22a of the crystal also aides in maintaining a suitable seal.

The peripheral shoulder portion 25 in the outer surface of the crystal 22 is clearly visible in FIGURES 3 and 4. The provision of the annular step 25 permits the multiple gripping fingers of a conventional crystal wrench or the like to be placed in firm engagement with the vertical wall of the step thereby permitting the crystal to be quickly and simply removed from the casing without any substantial likelihood that the gripping lingers will slip onto the crystal face with resultant scratching thereof.

While particular embodiments of the present invention have been shown and described, it is apparent that various changes and modifications may be made Within the true spirit and scope of this invention.

I claim:

1. A watch comprising:

a peripheral casing member including an interior wall portion defining a central opening in said casing member and having an interior peripheral flange member of predetermined thickness extending inwardly from said interior wall portion, said flange effectively separating said casing member into an upper and lower section;

a watch mechanism including a top dial and a transverse bottom casing member adapted for insertion into said lower section of said peripheral casing member with said bottom casing member in locking engagement with said peripheral casing member; and

a transparent crystal member having a peripheral contour complementary to that of said interior wall portion of said peripheral casing member and further having a stepped peripheral shoulder portion for adapting said crystal member to seat on the top surface of said flange member with said peripheral contour of said crystal member contiguous to said interior wall portion of said peripheral casing member and further with said stepped shoulder portion extending below said top surface of said flange member for at least a predetermined distance not exceeding said predetermined thickness of said flange.

2. The invention of claim 1 in which said crystal member is composed of a resilient co-polymer material and is seated in said peripheral casing member under a predetermined compression.

3. The invention of claim 2 in which said dial of said Watch mechanism is adapted to firmly engage the coplanar bottom surfaces of said flange member and said shoulder portion of said crystal to positively locate said clock mechanism between said dial face and said bottom casing member.

4. The invention of claim 3 in which said interior wall portion and said peripheral flange of said casing member are of an annular contour.

5. The invention of claim 4 in which said peripheral shoulder portion of said crystal is contiguous the interior face of said flange member to form a generally Z-shaped seal between said crystal member and said peripheral casing member for substantially preventing foreign matter from entering said watch casing between said crystal member and said peripheral casing member.

6. In a wristwatch of the type including a peripheral casing member having an interior wall portion defining a central opening in said casing member and having an interior peripheral iiange member of predetermined thickness extending inwardly from said interior wall portion, the improvement comprising:

a transparent crystal member adapted to seat against the top surface of said flange member with the periphery of said crystal member contiguous said interior wall portion and in compressed engagement therewith, said crystal member including an integral 5 6 stepped shoulder portion adapted to extend below References Cited the top surface of said flange for at least a predeter- UNITED STATES PATENTS mined distance not exceeding said predetermined thickness with said shoulder portion being contiguous 2,308,189 1/1943 Mam 58-90 the interiorally facing surface of said flange member over at least the major portion of the circum- 5 FOREIGN PATENTS ference of said flange member. 257,781 10/ 1948 Switzerland. 7. The invention of claim 6 in which said crystal mem- 316,835 10/ 1956 Switzerland. ber is formed to dene a peripheral step in its outer sur- 433,126 9/ 1967 Switzerland.

face for enabling said crystal member to be conveniently 10 removed 'from said casing by a conventional crystal RICHARD B- WILKINSON, Pflmay EXamlIlel WfeIlCh- G. H. MILLER, JR., Assistant Examiner 

